DUSP1 and IgA glomerulonephritis: Immunohistochemical staining of samples from patients with IgA nephropathy, membranous nephropathy or minimal change disease and samples from nephrectomy controls indicated that the protein expression level of DUSP1 was significantly lower in the IgA nephropathy and membranous nephropathy samples than in the nephrectomy control samples (Figure 2A).